van Geene Yvette, van Swieten Henri A, Noyez Luc
Department of Cardio-Thoracic Surgery, Heart Center, Radboud University Nijmegen, Nijmegen, The Netherlands.
Interact Cardiovasc Thorac Surg. 2010 Mar;10(3):413-6. doi: 10.1510/icvts.2009.216408. Epub 2009 Dec 15.
Troponin is a specific marker of myocardial damage. Increased troponins, however, are observed after almost all cardiac surgery. The clinical significance of this elevation is controversial. The aim of this study was to evaluate if troponin I (cTnI) measured 1 h after cardiac surgery provides additional information to identify patients at risk for hospital mortality.
Nine hundred and thirty-eight patients undergoing cardiac surgery between October 2006 and June 2008 served as development set. This group included 688 isolated CABGs and 250 valvular (+CABG) operations, and cTnI levels were measured 1 h (cTnI) after surgery. Hospital mortality, defined as death occurring at the Radboud University Nijmegen Medical Centre (UMCN) at any time after surgery, is the studied outcome. To assess the value of cTnI as a predictor for hospital mortality, receiver-operator characteristic (ROC) curves were used. The Youden-index was used for identifying the best cut-off point. Five hundred and seventy-nine patients undergoing cardiac surgery between July 2008 and February 2009 served as validation set.
The median cTnI level was 1.3 microg/l, 75% inter-quartile range (IQR) 0.68-2.59 microg/l. Ten patients (1.1%) died, cTnI release of the dead, median: 6.8 microg/l was significantly higher than the measured values in the group of survivors, median: 1.3 microg/l (P<0.001). Regression analysis showed a significant correlation between cTnI and hospital mortality (P<0.001). The ROC indicates a cTnI level of 4.25 microg/l with a ROC of 0.80 as optimal cut-off point for predicting hospital mortality, with a sensitivity of 70% and a specificity of 89%. Addition of type of surgery, isolated CABG vs. valve surgery, acute vs. elective surgery and EuroSCORE class did not improve the ROCs. In the validation set, the median cTnI level was 1.17 microg/l. Fifty-six patients had a cTnI level >4.25 microg/l. Of the 579 patients, 11 patients (1.8%) died, six of them had a cTnI level >4.25 microg/l.
Postoperative cTnI level, measured within the first hour after cardiac surgery, can identify a subgroup of patients with increased risk for hospital mortality. These patients may benefit from better monitoring, eventually with specific diagnostic and therapeutic interventions.
肌钙蛋白是心肌损伤的特异性标志物。然而，几乎所有心脏手术后均可观察到肌钙蛋白升高。这种升高的临床意义存在争议。本研究的目的是评估心脏手术后1小时测得的肌钙蛋白I（cTnI）是否能为识别有医院死亡风险的患者提供额外信息。
2006年10月至2008年6月期间接受心脏手术的938例患者作为开发组。该组包括688例单纯冠状动脉旁路移植术（CABG）和250例瓣膜置换术（+CABG），术后1小时测量cTnI水平。研究的结局是医院死亡率，定义为在拉德堡大学奈梅亨医学中心（UMCN）术后任何时间发生的死亡。为评估cTnI作为医院死亡率预测指标的价值，采用了受试者操作特征（ROC）曲线。用约登指数确定最佳切点。2008年7月至2009年2月期间接受心脏手术的579例患者作为验证组。
cTnI水平中位数为1.3μg/l，四分位数间距（IQR）的75%为0.68 - 2.59μg/l。10例患者（1.1%）死亡，死亡患者的cTnI释放量中位数：6.8μg/l显著高于存活组的测量值，中位数：1.3μg/l（P<0.001）。回归分析显示cTnI与医院死亡率之间存在显著相关性（P<0.001）。ROC曲线表明，cTnI水平为4.25μg/l时，ROC为0.80是预测医院死亡率的最佳切点，敏感性为70%，特异性为89%。增加手术类型（单纯CABG与瓣膜手术）、急症与择期手术以及欧洲心脏手术风险评估系统（EuroSCORE）分级并不能改善ROC曲线。在验证组中，cTnI水平中位数为1.17μg/l。56例患者的cTnI水平>4.25μg/l。在579例患者中，11例患者（1.8%）死亡，其中6例患者的cTnI水平>4.25μg/l。
心脏手术后第一小时内测得的术后cTnI水平可识别出医院死亡风险增加亚组的患者。这些患者可能受益于更好的监测，最终可能受益于特定的诊断和治疗干预措施。
